Medical facilities, laboratories, and other facilities can have specially constructed rooms that are used for conducting procedures or operating equipment that is sensitive to environmental radio frequency interference or subject to TEMPEST requirements. These rooms can be used for magnetic resonance imaging or other applications where environmental radio frequencies could impede performance of the equipment. In some situations, such rooms can also protect against evesdropping. Generally, these specially constructed rooms are designed to prevent or attenuate environmental radio frequency interference from entering or leaving the room. Environmental radio frequency interference can come from any number of sources, such as television and radio signals, power equipment, motors, fluorescent lights, computers, other medical equipment, and the like.
Part of the specialized construction for these rooms includes special doors and door frames that are designed to prevent or attenuate environmental radio frequencies from entering these rooms. These types of doors generally have a gasket positioned between the door and the door frame. The gasket is compressed between the door and the door frame to make a seal that prevents or attenuates radio frequency transmission from passing between the door and the door frame. A sufficient seal is generally made when the gasket is compressed by about 30 percent to about 50 percent between the door and the door frame. The force necessary to close the door and properly compress the gasket is dependent upon the thickness of the gasket installed. Consequently, larger gaskets generally require more force to compress. Depending upon the size of the gasket installed, radio frequency doors generally require between about 150 and about 450 pounds of force to move the door closed against the door frame to create a radio frequency seal. Accordingly, some conventional doors require slamming the door shut to produce the necessary closing force to latch the door and sufficiently compress the gasket.